The objective of this project is to elucidate the inter-relationship between molecular composition and topographic arrangements of membrane building blocks with reference to plasma membrane functions. Bioelectrogenesis, transport and other metabolic phenomena are based on the proper function of characteristic membrane subassemblies. Plasma membranes are studied after isolation from tissues or in intact cells of CNS derived tissue cultures. In particular the function of membrane ecto-enzymes has been the objective of this study. Experiments on seizure-prone animals indicate that malfunctioning ecto-enzymes in the brain are related to the biochemistry of convulsive disorders. The biochemical lesion in animal models of idiopathic epilepsy seems to be associated with a derangement of nucleotide metabolism in glia cells. Molecular probes are used to characterize individual membrane molecules. Synaptosome-like vesicles enveloped in plasma membrane are exfoliated from cells and appear to serve transport function.